iOS-计算webview占用高度

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
    [webView evaluateJavaScript:@"document.body.offsetHeight" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
        CGRect frame =webView.frame;
        frame.size.height =[result doubleValue];
        webView.frame = frame;
    }];
}